1. Field of the Invention
The present invention relates to apparatus and method of fabricating a substrate, and more particularly, to system and method for supplying functional water to a substrate cleaning apparatus.
2. Description of the Related Art
During a variety of process steps for fabricating an integrated circuit using a semiconductor substrate, impurities, such as residual chemicals, small particles, contaminants and the like are generated. To remove these impurities, a process step of cleaning the semiconductor substrate is required. In particular, it is very important to remove fine contaminants attached on a surface of the semiconductor substrate in fabricating a highly integrated circuit.
Recently, a method of cleaning the substrate using a functional water, such as hydrogen water, oxygen water or ozone water is used. FIG. 1 is a view schematically showing a functional water supply system generally used. Referring to FIG. 1, a functional water generator 12 generates a functional water by contacting a gas with a deionized water, and directly supplies the generated functional water to a nozzle 20 in a process unit through a supply pipe 16. While the process unit is in non-operation state, the functional water is discharged to an outside through a drainage pipe 18, so that the functional water is wasted.
Also, a concentration meter 14 for measuring concentration of a gas dissolved in the functional water is disposed adjacent to the functional water generator 12. The concentration meter 14 allows the functional water to be discharged until the concentration of the gas dissolved in the functional water reaches a set concentration range, and it allows the functional water to be supplied to the system when the concentration of the gas dissolved in the functional water maintains the set concentration range. Thus, since the related art functional water supply system discharges the functional water to an outside until the concentration of the gas dissolved in the functional water reaches the set concentration range, it too much wastes the functional water. Also, since the concentration of the gas is measured at a position adjacent to the functional water generator 12, the measured concentration may be higher than an actual gas concentration due to a residual gas which is not completely dissolved, so that a process failure may be caused.